Rock drill



J. C. CURTIS Jan. 4, 1944.

ROCK DRILL Filed Feb. 28, 1940 2 Sheets-Sheet 2 azz@ Patented Jan. 4,1944 ROCK DRILL John C. Curtis, Claremont, N. H., assigner to SullivanMachinery Company, a corporation of Massachusetts Application February23, 1940, Serial No. 321,346

(Cl. Z55-45) 1) Claims.

This invention relates to rock drills, and more particularly toimprovements in the feeding mechanism of a hammer rock drill of themounted type.

In hammer rock drills of the mounted type wherein a feed chain isemployed to effect drill feed relative to the drill guide, the feedchain is often operated by an independent motor mounted on the drillguide and operatively connected to a feed sprocket which engages anddrives the feed chain. The feed chain is guided for circulation on theguide and the ends of the feed chain are usually rigidly connected to apart of the drill hammer motor so that the longitudinal vibrations setup within the hammer motor during operation thereof are transmitteddirectly to the feed chain. Since one run of the feed chain is not undertension, the slack of the chain is suddenly taken up upon each forwardlongitudinal movement of the hammer motor, and as a result substantialjars or shocks are transmitted to the feed chain, thereby notonlyreducing the life of the chain but greatly increasing the vibrations setup Within the entire drill and decreasing drilling efficiency.

From one of its aspects the invention may, in a preferred embodiment,include means forming a guideway, means for effecting movement of anelement supported by said guideway along the latter, a hammer motor, andmeans for supporting said hammer motor for movement along the guidewayproviding a lost motion connection between the motor and the movementeffecting means. Thus, the motor may, within the contemplation of thisaspect of the invention, either be directly guided on the guidevvay andhave a lost motion connection with a feed chain or the like, or besupported, as in the illustrative embodiment hereinafter disclosed, uponan element guided on the guideway and moved along the latter by feedingmeans, and have a limited sliding connection with such element.

From another aspect the invention may, in a preferred embodiment,include a hammer motor, and feeding means therefor including anelongated chain loop and means positionable in various selectedpositions with respect to the loop of the chain for controllinfr feedand in each of such positions, selected for convenience of access,coacting in like manner with the chain on the effecting of feed.Obviously, from this aspect, the invention may be embodied not only inindependently power circulated chain or other flexible element feeds butalso in "jump type feeds with flexible element loops having associatedcontrol means.

From still another aspect the invention may comprise improved means formaintaining effectivecooperative relation between a chain utilized infeeding and a sprocket rotatable during feeding including a chainguiding roller arranged with its axis in a common plane with thesprocket axis, said plane substantially perpendicular to the run ofchain between the sprocket and the roller.

Other aspects of the invention will be apparent from the objects now tobe enumerated, and the detailed description of a preferred embodiment,and the several appended claims.

An object of this invention is to provide an improved rock drill feedingmechanism. Another object is to provide an improved rock drill feedingmechanism having improved means for reducing to a substantial extent thetransmission of the longitudinal vibrations of the drill hammer motor tothe feeding elements of the feeding means. A further object is toprovide an improved feeding mechanism of the motor operated, chain andsprocket type. Still another object is to provide in a feeding means ofthe above character improved means for substantially reducing the shockstransmitted to the feed chain. A still further object is to provide animproved mounting for the drill hammer motor whereby the transmission ofthe hammer motor vibrations to the feed chain is substantially reduced.Yet another object is to provide an improved sliding connection betweenthe drill hammer motor and the feed chain whereby the vibrationstransmitted to the side of the feed chain not under tension aresubstantially reduced. A still further object is to provide in a feedingmeans of the above character, improved means for facilitating release ofa stuck drill steel. Other objects and advantages of the invention will,however, hereinafter more fully appear.

In the accompanying drawings there is shown for purposes of illustrationone form which the invention may assume in practice.

In these drawings- Fig. 1 is a side elevational view of a rock drillconstructed in accordance with an illustrative embodiment of theinvention.

Fig. 2 is a view in central longitudinal vertical section taken throughthe rock drill shown in Fig. l, parts being shown in elevation tofacilitatey illustration.

Fig. 3 is an enlarged fragmentary View taken in the plane of Fig. 2,showing the improved hammer motor mounting with the parts in forwardfeeding position.

Fig, 4 is an enlarged cross sectional View taken substantially on line4--4 of Fig. 2.

Fig. 5 is an enlarged view in longitudinal section taken substantiallyon line 5-5 of Fig. 2.

Fig. 6 is a view similar to Fig. 3, showing the parts in the reversefeeding position.

Fig. 7 is an enlarged detail sectional view taken on line 1-1 of Fig. 2.

Fig. 8 is an enlarged detail sectional view taken on line 8 8 of Fig. 2.

In this illustrative embodiment of the invention there is shown a hammerrock drill of the mounted type generally comprising a drill hammer motorI, a drill guide 2 and feeding means generally designated 3, While therock drill disclosed is shown in a vertically disposed drilling positionand mounted on a column bar, it will be obvious that the same'may bedisposed in any desired drilling position and mounted in any suitablemanner.

The drill hammer motor I is of a conventional design and comprises amotor cylinder 4 containing a usual reciprocatory hammer piston fordelivering impact blows to the shank of a drill steel 5 having a usualdrill bit 6. The drill steel, as is usual in drill hammer motors of thetype disclosed, is suitably supported in a front chuck housing 1 of thehammer motor. A rear head 8 has connected thereto a supply hoseconnection 9 for conducting pressure iuid to the motor cylinder. Thechuck housing, rear head and motor cylinder are maintained in assembledrelation by side rods I0. As is usual in drill hammer motors of the typeshown, the hammer piston, as it is reciprocated in the motor cylinder,sets up longitudinal vibrations in opposite directions, due to suddenreversals in the directions of piston movement.

The drill guide 2 comprises a pair of parallel guide elements II, I Iherein in the form of channel irons arranged in face to face, spacedapart relation with their flanges I2 projecting outwardly in oppositedirections at the opposite sides of the guide, thereby to provide guideelements, as will later be explained. The channel irons II are rigidlysecured together by bolts I3 which pass through spacing sleeves I4, inthe manner shown in Fig. 4. A sliding trunnion support I5 has guidewaysslidably engaging the outer channel iron flanges and is adapted to beclamped in position by clamping elements I6 held in position by boltsI1. Simply by loosening the -bolts I1, the trunnion support I5 may beslid into different guide-supporting positions longitudinally withrespect to the channel irons, and by tightening the bolts I1 thetrunnion support may be firmly clamped in the desired adjusted position.The trunnion support has a usual swivel plate I8 adapted to be clampedin a usual saddle I9 mounted on a column bar 29. Supported at theforward end of the guide is a drill steel centralizer 2I of aconventional design adapted to embrace the drill steel 5 for guiding thelatter during starting or spotting of a drill hole in a well knownmanner.

Now referring to the improved feeding means 3, it will be noted thatsecured by a clamp 22 to the outer side of the guide and slidinglyengaging the outer flanges of the channel irons is a gear housing 23which supports a feeding motor 24 herein of a conventional pressurefluid actuated type. Keyed to the motor power shaft 25 is a worm 23meshing with a worm wheel 21 in turn keyed to a shaft 28. Fixed to theshaft 28 is a feed chain sprocket 29 which engages and drives a feedchain 30. Journaled on the sleeves I4 are guide rolls 3| engaging theopposite runs of the feed chain which extend longitudinally inparallelism with the inner and outer sides of the'channel irons, forguiding the chain for circulation with respect to the drill guide. Thefeed sprocket 29 is, as shown in Fig. 4, located directly opposite to aguide roll 3I so that the sprocket teeth are maintained in effectiveengagement with the feed chain. The feeding motor supporting housing 23is adjustable longitudinally of the guide and may be secured by theclamp 22 to the outer` channel iron flanges in any desired predeterminedposition opposite one of the guide rolls 3I intermediate the end guiderolls, there being provided in the channel iron ange adjacent each guideroll a notch 32 for receiving a holding pin 33 secured to the clamp.Such feed motor adjustment enables positioning of the feed motor nearthe rear end of the guide during up-hole drilling and near the front endof the guide during down-hole drilling, thereby to facilitate control ofthe motor by the operator. The feeding motor 24 has a usual reversingvalve 34 and the housing carries a throttle valve 35 for controlling thesupply of pressure fluid from a supply hose connection 36 to the hoseconnection 9 for the drill hammer motor. 'Ihe throttle valve 35 alsocontrols the supply of pressure fluid from the supply hose connection 36to the motor 24, under the control of the reversing valve. The bolt I3for the rearmost guide roll 3| is arranged to move in longitudinal slots31 in the channel irons I I and has connected thereto a yoke 38 havingan adjusting screw 39 engaging an end plate 4U se-` cured to the upperends of the channel irons. When the rearmost bolt I3 is loosened and theset screw 39 is properly adjusted, the upper guide roll may be adjustedlongitudinally of the drill guide to vary the tightness of the feedchain in an obvious manner, and thereafter the bolt may be tightened tohold rmly the guide roll in its adjusted position.

y Mounted on the drill guide for movement longitudinally therealong is asliding frame 4I having longitudinal guideways 42 slidingly receivingthe inner guide flanges of the channel irons. Secured by longitudinaltie bolts 43 to the sliding frame 4I are front and rear cross framemembers 44 and 45, and the ends of the feed chain 39 are secured at 43,46 to the front cross frame member 44 in the manner shown in Fig. 3. Thedrill hammer motor has a longitudinal sliding connection with thesliding frame 4 I, and to providel such connection the motor cylinder 4has integral lateral guides 41, 41 slidingly received in longitudinalguideways 48 in the sliding frame. The hammer motor cylinder guides havelimited longitudinal movement in the guideways 48 of the sliding frame4I, and these motor cylinder guides have opposite end abutment surfaces49 and 5U adapted selectively to abut against the cross frame members 44and 45 respectively. The teeth of the worm gears 2S, 21 in the drivebetween the motor power shaft 25 and the chain sprocket 29 areself-locking and serve to hold the drill hammer motor against movementrelative to the drill guide when the feeding motor is stopped, therebypreventing undesired movement of the hammer motor along the guide.Secured to the sliding frame 4I is a stop member 5I which is adapted toabut the rear channel iron plate 40 to limit the rearward movement ofthe drill hammer motor along the drill guide.

The mode of operation of the improved rock drill is as follows. The rockdrill is first properly set up with respect to the work with the swivelplate i8 of the trunnion support i5 firmly clamped in position' in thesaddle mounting it, in the manner shown in Fig. 1, with the drill steelengaged by the drill steel centraliser 2l. The operator may thenmanipulate the throttle valve 35 to admit pressure fluid from the supplyhose connection 36 to the hose connection il for the drill hammer motor,thereby to effect percussive actuation of the drill steel E, andconcurrently pressure fluid may be admitted, under the control of thereversing valve 313, to the feeding motor 24 to effect power rotation ofthe feed chain sprocket 2S through the worm gearing in a direction toeffect actuation of the feed chain t@ in the forward feeding direction.Initially, the drilling motor cylinder guides 41 are in the forwardposition shown in Fig. 6 with the abutment surfaces thereof in abuttingengagement with the front cross frame member M. When the drill hammermotor is fed forwardly along the drill guide into the position shown inFigs. 1 and 2, with the drill bit S of the drill steel engaging the faceof the Work, and feed is continued, the sliding frame 4l moveslongitudinally relative to the drill hammer motor cylinder guides el tobring the rear abutment surfaces 50 into engagement with the rear crossframe member d5, as shown in Fig. 3. When the rear cross frame member itis moved forwardly into abutting relation with the rear abutmentsurfaces 5i! on the motor cylinder guides, the drill steel is heldagainst the work. As the motor hammer piston percussively actuates thedrill steel, the drill hammer motor has alternating tendencies toforward and rearward longitudinal movements relative to the drill guidedue to the sudden reversals in the directions of movement of the hammerpiston, and the rearward longitudinal vibrations set up within thehammer motor are taken `by the tensioned run of the feed chain 3-9 whilethe forward vibrations are absorbed by the drill steel against the workdue to the sliding connection 4l, 58 between the drill hammer motor andthe sliding frame, thereby relieving the untensioned run of the. feedchain fromA any sudden shocks or which might be imparted thereto by thehammer motor. The direction of, feed may be readily reversed simply bymanipulating the reversing valve 34 to reverse the feeding motor,thereby to reverse the direction. of rotation of the feed chain sprocket2S, and as' the feed chain is actuated in the reverse feed eectingdirection, the slidingv frame lll is moved rearwardly upwardly along theguideways of the drill guide until the front transverse frame member Mabut's the front abutment surfaces 5l on. the motor cylinder guides, andthereafter the drill hammer motor and sliding frame move concurrentlyalong the guide. At that time the untensioned run of the feed chain 39is relieved of the longitudinal vibrations. of the drill hammer motor ina rearward direction. In the event the drill steel `binds or becomesstuck in the drill hole, the sliding connection lll, 43 between thedrill hammer motor and feed chain 3S enables the feeding motor, when thelatter is reversed to effect reverse feed, to come up to speed, beforethe lost motion Abetween the drill motor cylinder and sliding frame istaken up, and also, due to the sudden engagement of the front crossframe member 44 of the sliding frame with the hammer motor guidesurfaces e9, there is imparted to the hammer motor a decided jar orvibration in a rearward direction which is transmitted to the drillsteel to aid in the release of the latter.

As a result of this invention it will be noted that due to the improvedfeeding means the feeding elements are to a large extent relieved of theVibratory action of the drill hammer motor. It will further be evidentthat by the provision of the sliding connection between the drill hammermotor and the feed chain, the shocks imparted to the latter aresubstantially reduced, thereby not only reducing the Vibration of thecomplete drill but also reducing the wear and tear on the feed chain andincreasing drilling efficiency. Further, by the provision of the slidingconnection, release of a stuck drill steel is facilitated. Other usesand advantages of the improved rock drill will be clearly apparent tothose skilled in the art.

While there is in this application specifically described one form whichthe invention may assume in practice, it will be understood that thisform of the same is shown for purposes of illustration, and that theinvention may be modified` and embodied in various other forms withoutdeparting from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

l. In a rock drill, the combination comprising a guide, a hammer motormovable along said guide, a feed chain guided vfor circulation relativeto said guide and operatively connected to said hammer motor, a seriesof guide rolls on said guide for guiding said feed chain, and a motordriven feed sprocket engaging said chain at a point directly oppositeone of said guide rolls, said guide roll opposite said feed sprocketmaintaining the sprocket teeth in engagement with said feed chain andthe axes of rotation of said roll and sprocket lying in a commontransverse plane perpendicular to the longitudinal axis of said guide.

2. In a rock drill, the combination comprising a guide, a drill hammermotor movable along said guide and in which longitudinal vibrations inopposite directions occur during the operation thereof, means forfeeding said motor along said guide comprising a feed chain operativelyconnected to said hammer motor, a feed sprocket engaging said chain anda motor for driving said feed sprocket, and a longitudinal slidingconnection. between said hammer motor and said feeding means providingan operative connection therebetween, said sliding connection permittingfree and unimpeded movement of said hammer motor in the feedingdirection relative to said feeding means for relieving said feed chainof the longitudinal vibrations of hammer motor in said direction, saidsliding connection including a sliding frame guided for sliding movementlongitudinally along said guide and to which said feed chain isoperatively connected, said frame having longitudinal guideways and saidhammer motor mounted in said frame guideways.

3. In a rock drill, the combination comprising a guide, a drill hammermotor movable along said guide and in which motor longitudinalvibrations in opposite directions occur during the operation thereof,means for feeding said motor along said guide comprising a feed chainoperatively connected to said hammer motor, a feed having guidesslidably sprocket engaging said chain and a motor for driving said feedsprocket, and a free longitudinal sliding connection between said hammermotor and said feed chain for relieving the latter of the longitudinalvibrations of said hammer motor in one direction, said slidingconnection including a sliding frame guided for free sliding movementlongitudinally along said guide and to which said feed chain isconnected, said frame having longitudinal guideways, guides on saidmotor slidably mounted in said frame guide- Ways, and abutments on saidksliding frame for limiting movement of said motor guides relative tosaid sliding frame guideways.

4. In a rock drill, the combination comprising a guide, a drill hammermotor movable along said guide and in which motor longitudinalvibrations in opposite directions occur during the operation thereof,means for feeding said motor along said guide comprising a feed chainoperatively connected to said hammer motor, a feed sprocket engagingsaid chain and a motor for driving said feed sprocket, and alongitudinal sliding connection between said hammer motor and said chainfeed for relieving the latter of the longitudinal vibrations of saidhammer motor in one direction, said sliding connection including asliding frame guide-:l for movement longitudinally along said guide,said frame having longitudinal guideways, guides on said motor slidablymounted in said frame guideways, and means for limiting movement of saidmotor guides relative to said sliding frame guideways including crossframe members secured to said sliding frame at the opposite endsthereof, said feed chain being connected to one of said cross members,and abutment surfaces on said drill motor guides selectively engageableWith said cross frame members.

5. In a rock drill, the combination comprising a guide, a hammer motormovable along said guide, a feed chain guided for circulation on saidguide and operatively connected to said hammer motor, a feed sprocketjournaled on said guide and engaging said feed chain, a motor mounted onsaid guide for driving said sprocket, a stop on the rear end of saidguide, and a stop movable with said hammer motor and enga-geable Withsaid guide stop for limiting rearward movement of said motor.

6. In a drilling apparatus, in combination, means providing a guideway,a drilling implement, a hammer motor for actuating said drillingimplement and movable along said guidevvay and Within which longitudinalvibrations in opposite directions occur during the operation thereof,loop chain feeding means for imparting a feeding thrust to said motor inone direction including taut and slack runs of chain, and means forproviding a lost motie-n connection between said motor and said loopchain means for operatively connecting the same, said lost motionconnection exceeding the length of the forward longitudinal vibrationswhen said drilling implement is in engagement with the work, betweensaid motor and the slack run of said loop chain means, said lost mo-tionconnection permitting free and unimpeded movement of said hammer motorin the feeding direction relative to said feeding means for relievingsaid slack run of the vbratory action of said hammer motor during thedrilling operation.

7. In a rock drill, the combination comprising a guide, a drill hammermotor movable along said guide and in which motor longitudinalVibrations in opposite directions occur during operation thereof, meansfor feeding said motor along said guide comprising a flexible feedingelement operatively connected to said hammer motor, a feed memberengaging said flexible element and a motor for driving Said feed member,land a longitudinal sliding connection between said hammer motor andsaid flexible feeding element for relieving the latter of thelongitudinal Vibrations of said hammer motor in one direction, saidsliding connection including a sliding frame guided for movementlongitudinally along said guide, said frame having longitudinal-guideways, guides on said motor slidably mounted in said frameguideways, and means for limiting movement of said motor guides relativeto said sliding frame guideways.

8. In a rock drill, the combination comprising a guide, a hammer motormovable along said guide, a flexible feeding element guided forcirculation on said guide and operatively connected to said hammermotor, a rotatable feeding member journaled on said guide and enga-gingsaid flexible feeding element, a motor mounted on said guide for drivingsaid rotatable feeding ele ment, a stop on the rear end of said guide,and a stop movable with said hammer motor and engageable with said guidestop for limiting rear- Ward movement of said hammer motor.

9. In a rock drill, the combination comprising a guide, a drill steelactuator movable along said guide, feeding means foi` feeding said drillsteel actuator along said guide including a flexible feeding element, aseries of guiding elements at points spaced longitudinally of said guidefor guiding said flexible feeding element, a motor for driving saidfeeding means and operatively connected to said flexible feedingelement, said motor mounted on said guide for bodily adjustmentlongitudinally relative thereto, and means for adjustably securing saidmotor to said guide longitudinally of the latter in predeterminedpositions opposite any one of said guiding elements.

l0. In a rock drill, the combination comprising a guide, a drill steelactuator movable along said guide, feeding means for feeding said drillsteel actuator along said guide including a flexible feeding element, aseries of guiding elements at points spaced longitudinally of said guidefor guiding said flexible feeding element, a motor operated rotarydriving element engaging said flexible feeding element for actuating thelatter, and means for securing said rotary driving element to said guidein predetermined positions opposite any one of said guiding elementsWhereby the latter one of said guiding elements serves to maintain saidflexible feeding element in proper driven relation with said rotarydriving element.

JOI-IN C. CURTIS,

